Stem cell therapy for the hip.

Avascular necrosis, during surgery

When part of the ball of the hip loses its blood supply, surgeons drill the dead bone (core decompression) and can add your own bone marrow cells at the same time. This is the one hip use with controlled results.^[1][3]

Labral tears, impingement and tendons

Cells injected into the joint or tendon, or added during keyhole surgery. Here the evidence shows no benefit or does not exist.^[2][4][5]

Hip arthritis

Wear-and-tear arthritis is a different condition. See stem cells for arthritis.

The procedure

For avascular necrosis, one operation: marrow is taken from the pelvis and put into the drilled bone.^[6][7] Patients describe anything from same-day discharge to two nights in hospital, and weight-bearing rules that range from walking the same day to three months off the leg.^[8]

When it works, and how long it lasts

Patients describe the first change at two to three months, and the bone taking six to twelve months to heal.^[8] In the trials, the benefit is measured in years, but it is not permanent: 4 of 21 patients in one trial had a hip replacement within five years.^[9][10]

Who it suits, and who it doesn't

It only helps before the ball of the hip has cracked or flattened. Once it has, hip replacement rates were the same with cells and with saltwater.^[11] Older patients and people with larger areas of dead bone did worse.^[12][13]

Risks

Pain at the harvest site and the hip for a few days.^[6][14] Joint infection after an injection is rare, but in one series it needed an average of 3.6 further operations.^[15]

Is it better than core decompression alone?

That is the comparison the evidence answers, and it favours adding cells. No trial has tested cells for avascular necrosis without the drilling.^[3][1][22]

Does it regrow cartilage?

Not in any controlled study at the hip.^[16][23]

Do more cells give a better result?

Only up to about a million cells, after which repair flattened. The source of the cells made no difference.^[13]

Questions to ask a clinic

1. Is this avascular necrosis, arthritis or a labral tear? The evidence is different for each.
2. Has the ball of my hip started to collapse?
3. Will the cells go in during core decompression, or as an injection on their own?
4. How large is the area of dead bone, and what are my odds at that size?
5. How long will I be on crutches?
6. Does my insurance cover the cells, or only the drilling?